Mining operations often employ the use of a blasting system or apparatus for controlling actuation of an array of explosive charges. Typically, explosive charges are positioned at the blast site, for example in drilled boreholes, and detonators are associated with the explosive charges. During a blast event, signals may be transmitted to the detonators (often via shock tube, low energy detonating cord, electrical wires or wireless means) to cause initiation thereof, which in turn triggers actuation of each associated explosive charge. The efficiency and success of the blasting event may depend largely upon the careful positioning and timing of actuation of the explosive charges relative to one another.
During blasting operations, safety and security are paramount to blasting apparatuses, and those operating them. Over recent years, much research and development has provided improvements in safety, with the aim to minimize the risk of injury or death at the blast site. However, there remains significant room for improvements in both the safety and security of blasting apparatuses. In particular, the majority of the blasting apparatuses of the prior art include safety features designed to minimize the risk of inadvertent system setup, or improper or inadvertent detonator actuation, by an experienced blast operator. In contrast, perhaps less research and development can be attributed to the provision of blasting apparatuses that have restricted function in the hands of unauthorized users. For example, such unauthorized users may include children or terrorists. Examples of such systems are discussed briefly below.
In one example, International Patent Application PCT/AU00/00351 published Oct. 26, 2000 discloses a method and system for controlling a blasting network for use where spurious command signals may be passed through a blasting controller to the blasting network without the authorization of the authorized user, for example when the controller is connected to the Internet or an Intranet. The system includes a firewall whereby the communication link between the controller and the blasting network can be placed in a control mode by a switch. In the control mode, designated unsafe messages are prevented from reaching the blasting network.
In yet another example, U.S. Pat. No. 6,644,202 issued Nov. 11, 2003, discloses a method and apparatus for use in establishing a blasting arrangement by loading at least one detonator into each of a plurality of blast holes, placing explosive material in each blast hole, connecting to a trunk line a control unit that has a power source incapable of firing the detonators, sequentially connecting the detonators, by means of respective branch lines, to the trunk line and leaving each detonator connected to the trunk line. In addition the apparatus includes means for receiving and storing in memory means identity data from each detonator, as well as means such as a control unit for assigning a predetermined time delay to each detonator to be stored in the memory means. In this way, the detonators may be programmed to function only with the control unit and the control unit will function only with specific detonators, such that theft or other unauthorized acquisition of components of the blasting apparatus may be foiled.
The prior art discussed above illustrates various improvements in the development of blasting apparatuses, with the intention that they function only in the hands of authorized users. However, the consequences of blasting apparatuses, or components thereof, falling into the wrong hands can be severe, particularly if built-in countermeasures intended to prevent unauthorized usage can be foiled. For this reason, safety concerns remain paramount in the explosives industry, and there remains significant room for corresponding improvements in the safety and security of blasting apparatuses.